1. Technical Field
The present invention relates to the field of encoding and decoding of audio signals. More specifically, it relates to audio encoding and decoding systems (including MPEG-1 and MPEG-2 compliant systems) that enable variable playback of audio signals.
2. Description of Related Art
A conventional audio encoding system typically compresses an audio signal either to conserve storage space or prior to transmitting the audio signal. One method of compression involves the splitting of the audio signal into several frequency sub-bands before encoding (e.g., as utilized by motion picture expert group standards, MPEG-1 and MPEG-2 compliant encoding systems).
Conventional MEPG-1 and MPEG-2 compliant systems define several encoding schemes that utilize sub-band filtering for encoding audio-visual information. After encoding an audio signal using any one of these schemes, the encoded signal is either transmitted or stored for play back at some subsequent time. An audio decoder is then employed to decompress the encoded signal for play back.
When the encoded audio signal is played back at a normal rate using a conventional audio decoder system, the quality of the audio signal is relatively high. The user, however, may wish to increase or decrease the playback rate, e.g. at twice (2.times.) the normal speed. One example concerns the playback of video film for review where users wish to increase or decrease the rate of playback.
Conventional decoder systems are unable to playback audio signals at speeds other than normal. Further disadvantages of the related art will become apparent to one skilled in the art through comparison of the related art with the drawings and the remainder of the specification.